Evaporator devices of active substances are known of the type which use liquids such as fragrances and insecticides for the diffusion thereof in the air, which come with a wick partially immersed in the liquid which enhances the dispersion of the liquid in the atmosphere on reaching the surface of the wick exposed to the air.
Commercial products are also known which contain two immiscible liquids, termed two-phase devices. This type of device combines the action of two liquids, for example a fragrance with a biocide, a fragrance with an odor neutralizer or a fragrance with an insecticide or any other combination of volatile substances with or without active ingredients.
The immiscible liquids generally differ in that one of them has an aqueous base while the other has an organic base, the two liquids remaining in two layers with a well defined interface, the liquid of less density being in the upper layer.
In the patent of invention GB 2 371 750 a device is disclosed which contains a recipient with a mixture of two phases of immiscible liquids of different appearance, one of them contains a fragrance component which on diffusing in the air determines that the mixture takes on a different appearance to the mixture and therefore indicative of the activation of the device.
Another type of device incorporates a wick and contains two liquids which rise by capillary action through the wick, the liquids being designed so that the proportions of the formula are maintained during the entire lifetime of the product, for which reason it is necessary to have a precise definition of the wick and of the liquids.
This is the case of the device described in the patent of invention WO 2004/032620, wherein the wick is a single wick which comprises a first section of porous material of a certain size and a second section of porous material of greater size than that of the first section, such that in an initial phase in which the need exists to obtain maximum diffusion, the propagation is established of the liquid through both sections and in a subsequent phase only the first section disperses vaporized liquid into the atmosphere which is consequently spread in a smaller amount than in the initial phase.
In the patent of invention WO 2004/032983 a diffusion system is described based on a wick for the diffusion of two liquids having different properties held in one container, the wick being defined by two halves of different materials, a first half for the diffusion of a first liquid and a second half for the diffusion of a second liquid.
The fact that the halves of the wick are specifically defined in accordance with the characteristics of the liquid implies a multiplication in the specifications of the wick, since any variation in the formula of the liquid signifies a change in the properties of said halves.